Even though the Denver Broncos paid tens of millions of dollars for Russell Wilson to get off of their roster, Warren Moon says he's convinced the quarterback isn't washed ... telling TMZ Sports this week there's "no question, Russell can be very effective."
Moon -- a former Seattle Seahawk who stayed close with the franchise in retirement -- has seen the majority of Wilson's career up close ... and he seems sure that despite what the 35-year-old signal-caller has put on tape these past two seasons in Denver, he's still got juice left.